1. Field of the Invention
The present invention relates to a connecting structure for a piston rod in a tilt and trim mechanism for use with an outboard motor.
2. Description of the Relevant Art
U.S. Pat. Nos. 3,581,702, 3,722,455, and 4,720,278 disclose tilt and trim mechanisms for use with outboard motors for small ships such as motorboats, for example. Each of the disclosed tilt and trim mechanisms has tilt and trim cylinder units for tilting and trimming, respectively, the outboard motor by turning a swivel bracket of the outboard motor about a horizontal axis. The outboard motor is vertically moved above and below a water level by the tilt cylinder unit, and is also angularly adjusted below the water level by the trim cylinder unit.
As shown in U.S. Pat. No. 3,722,455 in particular, the trim cylinder unit comprises a cylinder fixed to the transom of a boat, a piston axially slidably fitted in the cylinder, and a trim rod having one end which is joined, e.g., welded, to the piston. The other end, i.e., outer end, of the trim rod is pivotally mounted on the swivel bracket of the outboard motor.
With the trim rod being conventionally joined to the piston in the trim cylinder unit, the tilt and trim mechanism is highly costly to manufacture.
In general hydraulic cylinder units, the piston rod is fixed to the piston by a bolt and nut mechanism. Such a connecting structure for the piston rod is also expensive.
The present invention has been made in an effort to eliminate the drawback of the conventional connecting structures for the piston rods used in tilt and trim mechanisms for outboard motors.